Iowa became the stage for electrifying political theater on caucus eve as six GOP presidential candidates tried to make a last-minute connection with voters — all while hounded by hundreds of reporters who documented their every move in mini messages on Twitter.

An expected 115,000 to 120,000 Iowa Republicans will record their choices tonight, GOP strategist John Stineman of West Des Moines estimated.

The race has shaped up as a three-way dead heat among Mitt Romney, Ron Paul and Rick Santorum, according to The Des Moines Register’s Iowa Poll, conducted last week. But in a sign of how unsettled the race remains, 41 percent of those who have a first choice could still be persuaded to change their minds, the poll found.

After 354 days of campaigning and more than 900 events, from the sweaty heat of the Iowa State Fair to skin-biting wind on Monday, the candidates are making their final arguments.

They spent the final full day of campaigning before the first-in-the-nation vote in one last-gasp scramble, traveling from town to city.

The words “mob scene” cropped up on Twitter throughout the day Monday to describe campaign events, but it was all relative.

“Callista and I are overwhelmed by the turnout this week,” tweeted Newt Gingrich, who drew 125 in Independence, then 225 in Walford.

A tiny cafe in Polk City, with a 49-person capacity, was quickly jammed for Santorum.

About 200 people were there, inside and outside, with a heavy load of reporters.

At a supply warehouse in Dubuque, 600 people were treated to “Eye of the Tiger” and “Born Free” as they waited to see Romney. And before more than 600 in Marion, an upbeat Romney declared: “We’re going to win this thing.” (Aides said later he was referring to the nomination.)

The frenetic politicking will continue yet tonight. All 4,000 to 6,000 caucusgoers in Black Hawk County will gather under one roof — inside the UNI-Dome, Black Hawk County GOP Chairman Mac McDonald said. They will be divided into precincts to vote, with cameras from Fox News and CNN watching, he said. At least two candidates — Michele Bachmann and Gingrich — are expected to make personal pitches there about 6 p.m.

Here’s how the final day before the Iowa caucuses went down, per Twitter and Des Moines Register reporters on the scene:

MITT ROMNEY

On the road from Davenport (crowd of more than 300), one of Romney’s sons posted a Twitter photo of his father on the campaign bus.

“One of the vents on the bus is blowing cold air, so the mittster is duct taping it closed. Typical dad,” Tagg Romney tweeted.

Romney held rallies in four cities Monday, more campaigning than he’s done in Iowa on a single day since the 2008 cycle. The leader in the Iowa Poll is banking on his electability as a key to success.

Ron Breitbach, 51, of Dubuque, who caucused for Romney in 2008 and plans to do so again tonight, said: “He’s a problem-solver. He’s a leader.”

Breitbach, who owns a golf course and sports center, added: “He’s had so much success, and that’s what we need — we need someone with success for people to rally around.”

RON PAUL

Paul, who tweaks reporters for discounting him, descended into their lair Monday, the Marriott in downtown Des Moines.

“Ron Paul no fool,” tweeted @RogerPolitico. “Holding rally in hotel where 400 reporters are staying. I think all of them are here.”

Some of the bigfoots: Maggie Haberman of Politico, Joe Klein of Time, Soledad O’Brien of CNN, Dan Balz of the Washington Post, Carl Cameron of Fox News and Chris Matthews of MSNBC.

Hundreds of people packed the hotel meeting room. Paul also drew 200 in Cedar Falls and 300 in Cedar Rapids.

The TV camera crews beelined to the men in the Des Moines audience with heavy facial hair, tattoos and nose rings.

Aaron Lea, a 34-year-old painter from Des Moines with a grunge look, was pressed for interviews by three news agencies within minutes.

“You wouldn’t see people like this at a Bachmann or Mitt Romney rally, so it makes it a point of interest,” said Lea, an independent who will register as a Republican at the caucuses.

Paul, a libertarian-leaning Texas congressman in second place in the Iowa Poll, often starts out his speeches by attacking the sacred cow of military spending and predicts a looming global financial collapse. On Monday, he boiled down his message to one word: liberty.

RICK SANTORUM

Santorum, a Christian conservative from Pennsylvania, said at the Reising Sun Cafe in Polk City that he has raised more money in the last few days than he did in the last few months.

The Register’s latest Iowa Poll shows Santorum in third place, and rising.

Glenn Larson, a retired insurance underwriter from Clive, said Santorum represents his values: opposed to abortion, in favor of balancing the budget.

“I think he has been neglected and pushed aside by the liberal news media because they think he can beat Obama. They don’t want him to win,” Larson said.

Santorum knocked his rivals a bit.

“We aren’t looking for a chief executive officer. We’re looking for a commander in chief,” said @JimAcostaCNN, who caught the jab at Romney.

A bus with “Santorum for President” on the side appeared on the trail Monday.

“Chuck Laudner says when Rick Santorum saw the big bus festooned with his name … he said ‘I’m not paying for THAT!’ ” the Los Angeles Times’ @RAbcarian said.

The RV is just on loan, driven by the Duggar family of Arkansas, anti-abortion activists with 19 children.

Santorum drew more than 200 at the Pizza Ranch in Boone, including Fox News’ Bret Baier. Later, 400 people chanted “We pick Rick!” at an Altoona Pizza Ranch.

“Young woman just fainted at Santorum event it is so crowded,” reported the Register’s @WilliamPetroski from Boone.

NEWT GINGRICH

Gingrich, who last month declared certain victory in the nominating contest, talked again Monday about what he said was the unfair influence of negative ads in Iowa, and sounded a note of caucus defeat.

Gingrich, a former U.S. House speaker, said: “It has nothing to do with governing America and solving our problems. It has everything to do with a very cheap and I think a very, very destructive model of politics, which is part of why Washington is sick today.”

At a later stop, he called the comment a mistake in wording, and pinned his hopes on the voters who say they could still change their minds.

Ed Larson and his wife, Janet, shook Gingrich’s hand, but they said they were not sure how they would caucus, since much of what happens depends on the consensus of their neighbors.

The Larsons downplayed Gingrich’s fourth-place ranking in the Iowa Poll. “It isn’t a concern because the polls are media-generated, and it changes every hour,” Ed Larson said.

RICK PERRY

“Perry press corp traveling 375 miles on the last day of the Iowa bus tour, ending the day with the stop we’ve all waited for — Perry, IA,” tweeted ABC News’ @ArletteSaenz.

When the Texas governor was introduced in Sioux City as the “next governor of the United States,” the crowd laughed. That got tweets with #oops hashtags.

Perry, who is fifth in the Iowa Poll, made a final plea to the crowd of 100: Decide by conscience, not poll numbers.

“A voter asks Perry what she can do to make him seem more electable in next 30 hours,” the Register’s @JoshHafner tweeted. “Perry says #iacaucus is just ‘mile one’ in a marathon.”

Perry said his campaign has the organizational endurance to win the nomination.

Jan Hansen, a teacher from Le Mars, decided in Sioux City that she’s caucusing for him. “I hear people saying all the time we need to choose the candidate that we feel is the most electable,” she said. “Vote your heart. That’s what he said.”

MICHELE BACHMANN

“Vote for a strong Iowa woman!” Bachmann told one backer amid a crush of people at Paula’s, a small restaurant in West Des Moines’ Valley Junction.

“You got a camera? We should take a picture. And then go home and Facebook it. Tell everybody to come out and caucus,” the Minnesota congresswoman said.

The crowd was in the dozens rather than hundreds. A team of 22 juniors and seniors from Blake School in Minneapolis was on a school-sponsored trip to witness the caucuses.

Bachmann, who had a horde of reporters turn up (Tucker Carlson, Andrea Mitchell and David Brooks),wandered to the Diggity Dog puppy treat shop, where her husband, Marcus, bought gifts for the family dog, Boomer.

Bachmann was up at dawn for TV appearances on “The Early Show” on CBS and “Morning Joe” on MSNBC. She ended her day with a 9 p.m. rally at campaign headquarters in Urbandale.

Standing on a pickup truck tailgate, Bachmann thanked perhaps 150 volunteers for their work on her behalf.

Des Moines voter Sally Mead said after hearing Bachmann in West Des Moines: “I’ll follow with whatever she has in mind that she thinks is right. She’s genuine.”

THEIR FINAL ARGUMENTS

One-sentence closing arguments, made in Iowa Monday: Why should you win the Iowa caucuses? Michele Bachmann: “We have one chance to repeal Obamacare; of all of the candidates that are running, I am the one with the deepest level of resolve to not quit until Obamacare is repealed.”

Newt Gingrich: “I am the only candidate who could successfully debate Obama in the fall, and I’m the only candidate who has an actual track record — twice, with Reagan and then as speaker — of actually changing Washington.”

Ron Paul: “We have to change things today and bring back the traditional America, which means liberty, peace and prosperity.”

Rick Perry: “I’m the one candidate who has a track record of executive governing experience to get America back working again, to create the jobs that will in turn create the wealth to get this country back growing economically.”

Mitt Romney: “For millions of Americans, the economy is in crisis today — and unless we change course with a new president, it’ll be in crisis for all of us tomorrow.”

Rick Santorum: “America needs someone with bold, courageous leadership who can make a difference, who can change the culture in Washington and be a strong commander in chief.”